I Know What You're Going to do Yesterday!
by Howard Hugheson
Summary: The world could face devastation beyond imagination if Phineas and Ferb don't trust and help a man who claims to be a time traveller from 2036, to solve a problem that could destroy computer mainframes worldwide.
1. Prologue

In memory of Lynda, my second mom.

THE FUTURE: YEAR 2036

The digital readout on the dashboard of the 1987 Chevrolet S10 Blazer glowed in the dark reddish-orange light the numbers 0.00047. This is exactly what he wanted and, pleased with that reading, he reached over to flip four switches, one at a time. Four lights followed, all next to the digital readout, as a low humming sound buzzed on.

Sitting on the seat next to him, leaning against yellow and black long metal compartment, were two pictures. One of the pictures was of a red-cushioned large chair with a bar in front of the seat, a purple light bulb on the top, some normal bulbs on the side and brass bars lining the outside of it. On the bottom of the photograph was a blank area which read: OWCA CLASSIFIED: DANVILLE MUSEUM OF NATURAL HISTORY, 2010. TIME DISPLACEMENT DEVICE.

Slowly he reached over, pushing the photograph aside so that he could see the other.

The other photograph was of two boys, and in the space under that it read: OWCA CLASSIFIED: PHINEAS FLYNN, FERB FLETCHER.

Then he looked to the picture next to it. A man, red haired, looking somewhat like Phineas, smiling at the camera and standing next to a large computer-like machine with a small screen on it. This picture read: OWCA CLASSIFIED: IBM 5100. COMPUTER SOFTWARE PROGRAMMER, ENGINEER: K. FLYNN.

Once more he looked to the display. The numbers on it did not change. A moment after he flipped the four switches, another digital readout turned on, this one glowing yellow at him. JUL 14 1975, it read.

"John," a deep and raspy voice said over a small speaker under the displays, perhaps where the radio in the truck should have been.

The man pushed a button and said to the speaker, "Here Major. The cesium clocks seem to be in working condition."

"Very good," the voice responded. "The computers are all checked. Magnetic housing units and electron injection manifold devices look good. Looks to be a smooth ride Agent T."

The man chuckled. "The agency must have a dozen Agent T's, sir. Save the Agent calling to the real Agents that deserve that title. John's good for me."

"Alright then John," the voice responded. "All looks good for a smooth trip. The divergence is well bellow 1%. The world line should be exactly like this one."

The man nodded and said, "Reading 0.00047 Major. I will say it's going to be weird to see the Tri-State area again. It's going to be weird seeing the United..."

"Stop that," the voice said, interrupting him. "We can't go on speculating what is and isn't, John. Stay with the mission. Remember, just like the boys when they found out about Agent P when they crossed the worldline divergence into our dimension."

The man leaned back in his seat. "Sorry sir," he said. "I wasn't much older than them at the time, you'll recall. It's strange that we'll be seeing them again. It's also somewhat strange that we're using the same technology that brought them here, to go back."

"Doofenshmirtz's, yes, I can appreciate the irony. John, everything is set. Remember your mission. Get the computer. The boys will know what to do concerning the Y2K38 problem. Just get them that computer."

"And you're sure that... he... is Phineas' uncle?"

"Yup. Don't tell either him or Phineas any more than they absolutely need to know. Phineas and his mom sure as heck don't need to know about Phineas' cousin, Sam. Neither of them need to know about any of it. As far as they know, Linda's brother vanished in the 1980's shortly after his company's breakthrough."

The man sighed, nodding slowly. "Here we go," he whispered to himself without holding down the button on the speaker so who he was talking to wouldn't hear him. Then he said, pushing the button again, "177th first mission is go."

"177 tempus edax rerum," the voice said. "Good luck, John."


	2. Chapter 1

Phineas laid on his back, staring up at the ceiling of his bedroom as he remained stretched out on his bed, his eyes partially closed in a sleepy manner.

Ferb blinked as he looked down at his brother, staring blankly at him.

"Oh, hey Ferb," Phineas yawned.

Ferb pointed at a desk clock which read 10:44 AM.

Phineas leaned up, stretching. "Yeah, sorry bro," he said, glancing to the clock. "I was up late last night, was listening to some late night radio show."

Ferb raised his shoulders as if shrugging, but holding them there, pausing before lowering them.

"Why?" Phineas asked, smiling. "Oh it was so cool, it was all about time travel. Some guy posted up some stuff way back, in the early 2000's I think, saying he was from the future and went back to the 70's to pick up some computer to solve some computer problem in his time. And he made some predictions that look like they came true."

Ferb blinked.

"Oh you know, like a second civil war. Man, imagine how Danville would look like in the Tri-State area if that didn't happen."

Ferb blinked again and looked forward, holding his hand up to his mouth questioningly.

"Eh, don't worry about it bro. I just thought it was cool since, y'know, we went back in time too. And that we went to the future. Oh, hey wait, this guy was from the future." Phineas narrowed his eyes thoughtfully. "This guy who posted this stuff seemed to be pretty accurate but, he said that a nuclear war happened in 2015, but the future we went to didn't look like it had survived a nuclear war, did it? I mean, I'm pretty sure Danville wouldn't be concerned about adding the extra wing to the museum if it had that to worry about."

Ferb blinked again, then flapped his arms.

"Oh yeah," Phineas said. "The flying car of tomorrow we were going to work on! I forgot all about it! Ferb, I know what we're going to do today!"

"Yes," said Ferb, "for today is yesterday's tomorrow."

Phineas looked puzzled at that. "Hey," Phineas said, "where was Perry yesterday?"

Perry snuck around to the back of the house, glancing around the corner as he slipped into the garage, closing the door quietly behind him. Slowly he opened the door of the family's car, pushed some numbers on the radio's display, and then the seat fell open, revealing a tunnel that Perry slide down.

When he reached the bottom of the tunnel hidden between the car's seat and his lair, he landed on his chair, looking up at the large screen, his eyes alert and ready for his orders from Major Monogram.

Sure enough, the Major looked down at the platypus from the large screen. "Agent P.," he said slowly, as if unsure of how to say whatever it was that he was about to say.

Perry's eyes went from the serious alertness which was his normal demeanor to confusion, and perhaps fear.

"Agent P.," Monogram continued, "this morning we received some disturbance in our central processor of the OWCA data retrieval system. There has been something that we have been, I guess you could say, glancing at, for some time now. We never thought it would amount to much though. We never thought it was real."

Perry looked confused now.

Monogram sighed. "Agent P., there was a long forgotten problem in the mainframe of every computer system in the world some time ago. It created quite a stir. A lot of heartache for a lot of people. There were many who feared that, at midnight on Near Year's on 2000, all of the computers in the world would reset themselves to 1900 instead of continuing on to 2000. They called it the Y2K problem."

Perry nodded his head quickly, indicated he understood.

"Well," Monogram continued, "of course it was a simple fix and it turned out to be a big red flag. However, there is another event just like Y2K, that should have been delayed until well into the future. Top computer engineers from around the world have been working on this. They call it Y2.038K. It would be basically just like what Y2K was suppose to have been, only it wouldn't have happened until the year 2038."

Slowly, Perry nodded indicating he understood, but this time with more curiosity, a brow raised in question.

"Agent P., I need you to pay very close attention to what I'm about to tell you. No one, not OWCA, not Homeland Security, not the President or the United Nations knows what is going on. We just received a model of what looks to be happening not in 2038, but something that will happen much sooner than expected, in 2015. Carl, run the demonstration."

A white box appeared above Monogram and to the right of him. Perry looked questioningly at it. It looked like a clock, with 0's and 1's above it.

"The zeroes and ones are binary, Agent P., which, as you know, is the basic computer language. The bottom you see is a clock. The time you see, and the binary readout, is what is suppose to be on every computer system in the world on the 19th of January in 2015, but watch."

Perry narrowed his eyes.

The clock read: 2015-01-19 03:14:04 (UTC). The numbers at the far right, what Perry assumed were seconds, counted up. 04, 05, 06, 07, but when it got to 08, the binary, the zeroes and ones in a nice pattern, suddenly read out a 1 followed by a long line of zeroes, and the clock itself read 1901-12-13 20:45:52.

Perry's eyes widen, and all he could do is point at the screen.

"That right Agent P.," Monogram continued. "On January 19, 2015, all of the computer systems, computer mainframes, central processors, all of every mainframe will reset itself back to 1901. This will cause mass chaos all over the world, but what is especially horrifying about this, is that Russia's nuclear warheads, most of which are aimed at the next most powerful superpower, that being us, will malfunction. Due to faulty programming on Russia's part and old computer hardware from the Soviet ages, it will send a signal for them to launch, and there will be no stopping it. The United States of America will be thrown into an all out nuclear apocalypse, and our leaders will be forced to fire back."

Perry's eyes only stared wide and horrified at Monogram.

"If..." Monogram hesitated, "if a World War 3 comes to mind, Agent P., you would be thinking accurately."

Perry slowly leaned back in his chair.

"We can say with certainty that Doofenshmirtz, and the other evil scientists, aren't behind this. They're actually working on their own solution privately but it's doubtful that they'll be able to come up with one any faster than we could. Here's the lowdown Agent P. It looks like when Y2K was stopped, the 'effects' that it would have brought were only prolonged. It's as if Y2K should have happened, and it not happening on that date only prolonged it by 15 years."

Perry nodded slowly, lowering his head slowly so that his eyes looked from the screen to the desk, the platypus looking as though he didn't fully believe what he was hearing.

Monogram cleared his throat. "This is no time for regrets or deep emotions, Agent P.," Monogram said. "Normally I'd send you on missions to stop Dr. Doofenshmirtz from doing some evil thing, but today I need you to try and persuade him to work with OWCA."

Perry's eyes widened again, and his beak dropped.

"I know it's unusual, but if there's any chance he or anyone can assist in this matter, we need he help. Go get him Agent P."

Perry reluctantly saluted, then walked off.


	3. Chapter 2

THE PAST: YEAR 1975

John stepped into the building which was the headquarters of the company International Business Machines. Looking around, he seemed satisfied that no one here was looking at him awkwardly. The man tried his best to wear a time-neutral outfit so that these people from the 1970's wouldn't know that he was actually from another dimension and 60 years into the future.

John cleared his throat nervously as he walked up to the reception desk. This was something that he had been training for in the army for almost a decade now, but even after all of the training he had, going back in time was still something that he couldn't exactly prepare for. "Excuse me," he said to the receptionist, a dark-haired woman looking to be in her late 40's, wearing an all grey suit. "I'm here to see Mr. Flynn."

The woman looked up at him through thick glasses which were attached to a chain that was hanging loosely from her neck. "Do you have an appointment?"

John nodded. "Yes," he said. "My name is John Titor."

John stood in the almost sterile computer lab staring down at his one of his mission's objectives: the computer which, at the time was new and revolutionary but to John was old a chunky. The IBM 5100. John sighed as he rubbed his unshaven face, his dark hair showing up more in his whiskers than Flynn's red hair would have. John didn't want to seem unkept in front of the man who could change the course of history by merely saying yes to his request, but he had no choice. John hadn't exactly thought about hygiene when he got into a time machine to go back in time by about 60 years.

Titor was a tall man who wore a brown jump-suit uniform. On his shoulder was an American flag, on the other was a circular patch with a strange pattern which read '177th'. On his uniform was a name tag, which read TITOR. On his uniform was also a rank, a golden leaf, indicating him as Major. Unless the person looking at him was especially observant, they would assume he was just another military personnel.

Titor looked away from the IBM machine when Flynn, wearing a business-casual attire with a loose tie, walked through the door. "You must be Maj. Titor," he said. "I'm Kevin. What can I do for you?"

Titor smiled. "Kevin, I'll be very frank with you. I'm here on a delicate mission ordered by a..." then he cleared his throat, "the Secretary of State of the United States."

Flynn sat down on a reclining office chair, leaning back and said, "Uh-huh."

Titor glanced to the computer. "We need to borrow a 5100."

"By borrow you mean take it without the intent on its' return," Flynn said with a smirk.

Titor looked to him with a nervous frown. "Mr. Flynn," he said, his voice gentle now, "that machine, your machine, is what stands between life on this planet, or this planet's demise. You can choose not to give it to me..."

Flynn laughed and pulled up a chair, sitting down. "No man," he said, "you got me wrong here. You can have the computer, I'm just curious as to why."

Titor raised a brow. Leaning forward, a slight smirk, he said, "Classified."

Flynn lazily glanced to the side, then back to Titor. "I'm letting you have one of IBM's pride and joys, something that would cost a normal person quite a bundle Major. I think I'm entitled to know."

"You wouldn't believe me," Titor said, his face serious again.

"I'm an open minded guy," Flynn said, resting his arms on his knees. "Try me."

Titor leaned back, sighing some in aggravation, his face exposing that emotion. "I'm from the future, and that machine may prevent every warhead in the world from launching all at once." Titor looked at the ground for a moment, then to Flynn, expecting to be laughed at.

Flynn smiled, but he didn't laugh. "Far out," he said flatly.

Titor looked surprised. "You believe me then?"

Flynn shrugged. "No reason not to," he said. "Where from in the future? How many years?"

Titor hesitated. "This is classified, Mr. Flynn."

Flynn chuckled. "It'll remains classified man. How far?"

Titor nervously looked to the computer. "2036."

Flynn laughed, jumping in his chair. "Far OUT!" he almost yelled, but kept his voice down to just a loud talk. "What is that like? Flying cars and stuff? Man, if you guys have time travel worked out..."

"A nuclear war killed many on the earth in 2015," Titor said, his eyes serious, "pushing us back several generations, and dividing the United States into several regions, with several Presidents. Our scientists and technicians made due, though. Your nephews being two of them."

Flynn raised his brows. "I'm gonna have nephews?" he asked.

Titor nodded. "I've said too much alright, Mr. Flynn."

Flynn laughed, holding up his hands as if to say he was surrendering. "Hey man, as far as I know, you were never here, and that 5100 you're taking was never manufactured."

Titor nodded, standing up. "I need to go," he said.

Flynn stood up also. "You'll need a box for that," he said, looking around the large room. When he found a box, he walked back to Titor and the computer which sat on the table he stood next to. "Just one more thing though. How do you know that coming back here, to get this, hasn't changed something that should happen in the future?"

Titor shrugged as Flynn packed up the computer. "Technically I'm from the future of another dimension. Time's funny like that, Mr. Flynn. You can move forward to the future with no problem, but you can't do that in what's called your own 'worldline'. You have to jump dimensions to another worldline. It's like two lines right next to each other, and you step on to the other one. There's an infinite number of those worldlines, but the closer the worldline you move to, the more it's like your own."

Flynn finished packing the computer. "Huh," he said. "Sort of like reflections in a mirror, right? You hold up two mirrors and the reflections from each one go on and on?"

Titor smiled. "You got it right," he said. "If you step into the reflection right next to you, it's almost like the same worldline you're on. The further reflections you go out, the more different the worldline you're stepping on becomes. We call it divergence. When we move through time like this, we try to get the divergence as close to zero and as far from one as we can."

Flynn paused, resting his hand on the box which contained the computer. "So, like, how do you know that just coming here and talking to me won't change the future of THIS worldline?"

Titor was quiet for a moment. "It could have I guess," he said after a moment. "It was a chance we had to take."

Flynn nodded slowly. "Well, Major, here's your machine. Good luck John."

Titor sighed, staring down at the box. "Look," he said, slowly looking back to Flynn, "I shouldn't be telling you this, but... there's something that you need to know about computer mainframes and the year 2000."


	4. Chapter 3

"So, Perry the Platypus," Doofenshmirtz said with a smile, "so nice of you to drop by. Unfortunately, no evil scheming today though, you probably knew that."

Perry had simply knocked on the door to be let in, which was unusual from the normal methods he used to enter the building (normally busting down a door or wall). Perry gave a slight salute to the man, as if to acknowledge that he indeed did know.

Doofenshmirtz nodded, a depressed look on his face as he turned and walked over to a computer. "You probably also know about the computer problem that will probably doom us all."

Perry smirked in a sad way, then nodded.

Doofenshmirtz sat down before the monitor. "You see Perry the Platypus, though I can build a mean inator, I'm not too good with computers. To be honest, all of the scientists in the League of Villainous Evildoers Maniacally United for Frightening Investments in Naughtiness can whip up some evil MACHINES, but they're not too good at evil computer SOFTWARE. That didn't stop me from looking up the problem though, and I got some pretty interesting results." Then he looked to Perry. "I actually got a lot of helpful information just by doing a search for Y2K38. I mean, don't you guys have any computers or anything?"

Perry shrugged.

Doofenshmirtz sighed. "Oh well, it doesn't matter Perry the Platypus. We're together in this one to prevent all of our mutual doom. So I looked up Y2K38 and Y2K together, and I found this."

Perry peered at the screen, then his eyes widened as he read.

Doofenshmirtz looked down at Perry. "Don't get too excited Perry the Platypus, these messages were only left during one small period of time on some bulletin board system way long ago." Then he laughed. "BBS, wow Perry the Platypus, do you remember those?"

Perry gave Doofenshmirtz an annoyed look.

"Oh, right," he said with a nervous smile. "Platypus, you probably didn't get online a lot back then in 2000, 2001 huh?"

Perry grumbled but looked back to the screen, then started scrolling through the text on the website using the mouse.

Doofenshmirtz didn't do anything to stop him as he also looked back to the screen. "It seems quite extraordinary and too coincidental not to be somehow connected to this computer thing. I kinda figured, you know, Occam's Razor and all of that."

On the screen was written a simple message. 'TimeTravel_0: Yes, the Pearl Harbor example relates to Y2K. Have you considered that I might already have accidentally messed up your worldline?'

"It was written between 2000 and 2001 by a guy who called himself John Titor," he said as he stared at the screen with Perry. Then he took the mouse and started scrolling through the website himself. "This guy claimed he was a time traveler from the year 2036, that he went back to 1975 to get this old computer from his grandfather. I guess he made a pit stop in 2000 to go see his family and get some pictures that were lost in a... and get this Perry the Platypus... a nuclear war that happens in 2015."

Perry blinked, looking up at him.

"So while visiting home, he posts this stuff up here, apparently not caring who doesn't or does find out about him. It struck me that the new Y2K problem was happening it 2015, with the potential to start a nuclear doomsday. It occurred to me that this Titor, by telling his grandpa about Y2K, only prolonged the inevitable."

A picture of the IBM 5100 appeared on the screen.

"From what I can find," Doofenshmirtz continued, "there was a programmer from IBM, who worked on this computer, who was credited as having fixed most of the Y2K problem back in the 1980's. That guy started this big company, but vanished off the face of the earth after the company went big. The guy's name was Flynn."

Perry's eyes widened, and his beak dropped opened.

"Kevin Flynn," Major Monogram said while reading over a report that Carl handed to him. "Founder of the company ENCOM. Vanished sometime in the 80's when his young son, Sam Flynn, inherited the majority of the company's stocks. Sam went on to have a son..." then Monogram's eyes widened. "Sam took the name of his mother, Leslie Titor. Great googly moogly Agent P., Doofenshmirtz was right! Kevin Flynn is the grandfather of John Titor who..." slowly, Monogram looked at Perry, and continued, "...who is at this time no older than the children in your host family, Phineas and Ferb..."

Perry slowly nodded, his eyes closed halfway, as if telling Monogram to keep going with this train of thought.

"Flynn," Monogram whispered. "Phineas Flynn. CARL!"

"Already got it sir," Carl said, bringing another report over to Monogram. "According to this, Kevin Flynn had two sisters, Linda and Tiana. Sir, John Titor is not only real but he's Phineas Flynn's second cousin, and Linda Flynn's great nephew... from the future!"

Monogram slowly looked down at Perry. "Agent P.," he said slowly, "see what you can find out about all of this. I'm going to contact the President, and notify him of this, in case anyone shows up claiming to be a soldier from the future. Agent P., secure your host family. If this Titor shows up, notify us immediately."

Perry saluted, indicating that he understood.

Monogram nodded. "Good luck, Agent P."


	5. Chapter 4

Phineas and Ferb both sat under the tree in their backyard, their backs leaning against it. Ferb stared at the house in the bug-eyed manner which was his usual look. Phineas' stare revealed boredom.

Then Candace walked up.

"Phineas," she said, looking annoyed, "I don't have to tell you that your friends are not allowed to call you using my phone, do I?"

Phineas leaned up, looking interested. "I didn't know any of my friends had your phone number sis," he said. "I don't think I know it by heart. Why? Did someone call?"

Candace sighed and shoved the phone towards her brother. "Make it a quick conversation or I'm telling mom," she said then crossed her arms, waiting.

Phineas, confused, accepted the phone, and held it to his ear.

Ferb blinked, watching him.

"Uh," Phineas said hesitantly, "hello?"

"Phineas Flynn?" asked a voice.

"Yes," Phineas replied, still hesitantly. "Who is this?"

Candace blinked when she heard Phineas say that, and her angered look turned to concern as she looked down at Phineas.

Perry watched from the other side of the yard. Though he hadn't been spotted yet, he kept his hat off just in case he was seen. The platypus' eyes narrowed as he listened in.

"You know my name," said the voice. "Looking over the record of your ISP account, I see you've read over some things I posted. Though, to you it was recorded over 10 years ago, for me it was only a few hours ago when I posted my last statement."

Phineas' eyes widened. "Ta..." he said slowly.

"John Titor," the voice replied. "Phineas, I can't exactly explain it in detail but, you and your brother possess some very valuable talents that would assist to prevent the end of your world. I need your help."

"What talents?" Phineas asked. "Why us?"

Candace frowned, visibly worried now.

"You have mechanical talents far superior to even the best of engineers. I need you to fix a problem that your government knows about but is helpless to do anything to stop it. Do you think that I'm lying? Ask your mother about Kevin. I will call this number back in 30 minutes." The call then dropped.

Candace snatched the phone from Phineas, closing it quickly. "What a weirdo," she said, her eyes narrowed. "Phineas, don't talk to this guy. I'm gonna call the police."

"No, wait a sec," Phineas said, slowly standing up, Ferb standing up with him. "I knew who that was. I read about him last night. If he is who I think he is, he's a time traveler and we can't really dismiss that since we traveled through time too, right? Ferb, that's who they were talking about last night on the radio!"

Candace looked confused. "Time traveler?" she asked.

Phineas shook his head. "No time, come on!"

Then he ran into the house, Ferb and Candace quickly running after him.

Perry watched, and once they were inside, he lifted the fur on his arm to reveal a wrist communicator. Monogram's image appeared almost instantly. "Is it Titor?" he asked.

Perry nodded.

"How in the world did he get that girl's phone number?" he asked himself. "Alright, keep a close eye out on the family, and this guy if he shows up Agent P. We'll be watching too, through your wrist communicator. Keep on it Agent P."

Perry saluted, then headed towards the house.

Phineas lead the trio into the kitchen, where their mother, Linda Flynn-Fletcher, stood over a pot cooking something.

Phineas nervously looked to Ferb, who only blinked at him, then to Candace, who stared at him in a way which revealed how scared she was.

Perry walked up to them and rattled his teeth.

"Oh, there you are Perry," Linda said as she turned, then blinked when she saw her children. "Kids, you scared me," she said, then frowned when she noticed the look in Phineas' and Candace's faces. "What's wrong? You guys look like you've seen a ghost."

Phineas slowly picked Perry up, hugging him as if trying to find comfort in the animal, and asked, his voice hesitant and slow, "Mom... who's Kevin?"

Their mother's eyes widened, her mouth dropped open, and the spoon she was holding fell to the floor, making a 'clinking' sound when it hit the ground. "Where... did you hear that name?"

Phineas rested his chin on Perry's head nervously. "Mom, please, who is he?"

Linda walked into the living room, disregarding both spoon and dinner, and sat down on the sofa. "Kids, sit down," she said, her voice soft, gentle.

All of them followed her, all of them sitting down as she requested.

"Kevin Flynn is my brother," she said, staring forward.

Phineas gasped, almost dropping Perry but grabbing hold of him tightly. Candace's reaction was almost the same, except without the platypus. Ferb blinked.

"We thought it best not tell you," Linda continued, "because he's been missing for so long, we just assumed the worst. In 1982, a company he founded grew, becoming huge. You might have heard of it, especially you boys. ENCOM."

Phineas said, quickly, "They make most of our video games! Mom, that company belonged to your brother?"

Linda held a hand up, as if asking for silence. No one said anything. Linda continued, "When the company hit big, Kevin simply vanished. Just disappeared, right off the face of the earth. The last person to have seen him was your cousin, a man named Sam."

Phineas once more looked shocked. "We have a cousin?" he almost demanded.

Linda's eyes filled with tears. "Kids, I'm so sorry I never told you, but Sam and I talked about this for a long time, and we both decided that it was best if you didn't know. Sam has his own family now, and a son too. Sam wasn't much younger than you two when his dad disappeared those many years ago."

Phineas slowly shook his head. "All of this time," he said, "we had an uncle we never knew about."

Linda sighed. "Like I said kids," she continued, "Sam now has a family of his own and lives an extremely private life. Now he owns ENCOM and, because of his fortune and the company's importance in the IT world, he doesn't want to endanger his family by being well known and famous. Sometimes he keeps in touch with me, and his own son was born not long before you kids."

Phineas glanced at Candace, who stared at him for a moment before both looked back to Linda. "Mom," Phineas said slowly, as if being careful to say the right thing, "what is Sam's son's name? Do you know it?"

Linda nodded. "John," she said, "but he kept his mother's maiden name, Titor."

A call never did come to Candace's cell phone as John had promised them, but a text message was sent. 'Have you talked to your mom? -JT'

Candace bit her bottom lip gently, looking between Phineas and Ferb. "You think I should reply?" she asked.

Phineas shrugged. "Call him," he said. "Why bother with texting?"

Candace shook her head. "No," she said, "I can't. The guy called from a restricted number, and he's sent this text through an email, not another cell phone."

Phineas then walked up to Candace, grabbing the phone.

"Hey!" Candace said, her face showing her anger, "that's my phone Phineas! No one uses it but me!"

Phineas waved her off as he began to type in his reply. "Yeah, and we'll make you another one if I break this one."

Candace humphed, looking to the side.

'Yes', Phineas typed in to the phone. 'You are Sam Flynn's son?'

Candace, though annoyed, leaned forward, looking at her phone.

Ferb, though his expression had not changed from its' usual blank stare, also leaned forward.

The phone beeped, indicating a message had arrived. Candace almost jumped. "Open it!" she snapped.

Phineas glanced at Candace nervously, then back to the phone, opening the message.

'Hey girl', it read, 'call me k? BFF! -S'

"Hey girl call me, S?" Phineas asked, a brow raised questioningly as he looked up at Candace.

Candace snatched the phone back from Phineas, even though Phineas had a surprised and almost angry expression when she did so. "It's Stacey," she said, beginning to type in her reply.

Then the phone beeped again. Another text.

"Gimme!" Phineas said, almost jumping for the phone, but Candace held it above her and out of his reach. "No way, I'm the older sister, this is MY phone, I'm in charge." Then, disregarding her reply to Stacey, she opened the text message that had just come through.

'Yes', it read. 'Your mom has kept up with my father at least some. Prepare to receive parcel this afternoon. Directions will follow. -JT'

Candace read it carefully, then reluctantly she showed Phineas and Ferb. Both boys read over it almost as carefully as Candace. "Parcel?" asked Phineas.

"Package," Candace said, closing the phone slowly, and holding it to her, as if the phone were some delicate thing ready to break if handled too hard.

Phineas rolled his eyes. "Candace, I know what a parcel is, I..."

"Excuse me," a voice said. This made all of them jump, even Ferb, then they turned to look at a delivery man at their fence holding a package. "This the home of uh," he looked at the address label, "Phineas Flynn and Ferb Fletcher?"

Phineas ran forward. "That's us!" he said, grabbing the package from the delivery man and almost dropping it. Ferb caught the underside of it before the package hit the ground however. "Man," Phineas said, putting it down slowly, "what's in this?" Then, without waiting for a response, he opened the package quickly. All of them, even the delivery man, looked down into the box curiously.

The old and outdated IBM 5100 almost stared back at them.

"Wow," the delivery man said, "would ya look at that. Some old computer. Hey, aren't you kids a little young to be ordering an old dinosaur like that?"

"Yes," Phineas said, "yes we are. That's because we didn't order it. It was sent to us." Then he reached into the box, pulling out a piece of paper. The directions, as promised. Phineas read over them, then his face grew into a slight panic, as if whatever was written on the paper scared him almost as much as the talk with his mom, or the call.

Perry stood off to the side, but lifted his fur slightly so that Monogram would have a good look at what was happening.

"Hey Phineas!" a familiar voice said. The smiling and cheerful Isabella hopped up to the fence and looked at everyone. Seeing the fear in both Phineas' and Candace's faces, and the package before them, her normal cheerful manner turned into a nervous pause. "Wh-Whatchya doin', Phineas?"

Phineas slowly looked to her. "Saving the world apparently," he said, his voice hardly above a whisper.


	6. Chapter 5

As Phineas continued to work on the computer, entering the various binary codes Titor had instructed him to enter, Ferb watched. After a moment, Ferb held up his hand looking at it.

Isabella blinked, looking to Ferb. "Ferb, what is it?" she asked.

"I was just thinking what the future would be like, if we grew an extra finger."

"Five fingers?" asked Phineas smiling. "That'd be pretty insane."

"You know," Isabella said, "readers are probably going to leave comments that this joke was already used in the Simpsons or something."

"What comments?" Phineas asked.

They all laughed.

"Alright," said Phineas, wiping his head with the back of his hand and standing up, "everything's been programmed, all of the binary set." Then he looked to Candace. "What next Candace?"

Candace shrugged. "Well, he said in the note just to wait for him to call," she said, shrugging. Just as she said that, her phone rang.

"Here he is," said Phineas nervously, glancing to Ferb and Isabella before looking back to Candace. "You uh, want me to answer it?"

Candace held the phone to her angrily. "No!" she snapped, "it's my phone, I'll do the answering." Then, slowly, she flipped it open and held it to her ear. "Um, hello?" she asked nervously.

There was a pause as they all looked at Candace.

"Look bud, it's MY phone," said Candace, "I'll do the... alright fine." Then she handed the phone to Phineas. "Guy's pretty persistent."

Phineas rolled his eyes as he took the phone, then said into it, "Hey cuz."

"Second cousins," the voice Phineas knew as Titor's replied. "Have you finished the programming yet?"

"It was difficult," Phineas replied, looking down at the old computer, "but we got it."

"Alright," Titor said. "Listen to me very carefully. You canno-..."

"Huh?" asked Phineas, then looked down at the phone. "Looks like the signal cut out. I think he was about to say cannot. We cannot, something."

Ferb blinked. Then pointed.

All of them turned towards the direction that Ferb pointed. Coming up the driveway was a large white van. It was unmarked, a man driving and a woman in the passenger seat. Both had on well tailored suits.

The van pulled up and stopped, both of them getting out. "Excuse me," said the man, walking up to the gate and looking down at the kids, the woman next to him also looking at them. "Is this the Flynn-Fletcher residence?"

Candace grabbed her phone from Phineas. "Who's asking?" she asked, her eyes narrowed.

The man and woman looked at each other, then turned back to face the group. "We're from a group called the European Organization for Nuclear Research. Our labs are based in Switzerland but, we were told that someone here in the Tri State area, going by your name, had in their possession an IBM 5100 which had been programmed to fix a Y2K 2015 problem."

Phineas leaned over and whispered to Ferb, "Hey Ferb, we were at an award ceremony in Switzerland when we went into the future, remember?"

Ferb nodded quickly, looking back.

Phineas faced the two adults. "We have it," he said. "Were you meant to fix that problem using this computer?"

The man nodded quickly. "Yes," he said, "we must get it to the proper authorities quickly. Is this the IBM 5100?" Then he nodded to the computer sitting on the lawn.

"Why yes," Phineas said, "yes it is." Then he went over and picked up the old computer with some effort, and carried it over to the adults. "Here you go," he mumbled, then let out a phew as the man tool it carefully out of Phineas' arms. "Why would you need an old computer to do that, anyway? Putting in the program specs was a lot harder than using just a normal computer."

The man smiled gently. "In order to fix all of the mainframes," he said, "we couldn't use a current computer. We had to go back and try to find a computer that was used to create the original systems that the current OS's are based on."

"OS?" Isabella asked curiously.

"Operating System," Phineas said to her. "It's what we use to operate computers. Y'know, like Doors 2000."

"Oh," Isabella said, smiling as she understood.

The man nodded. "Well, we'd better get this back to Geneva kids. You've done great here."

The two went back to their van, and drove off. That's when Phineas noticed the odd logo on the side of the van, interconnected circles with the word CERN printed in the center.

"Huh," Phineas said curiously, his eyes following the van as it went down the street. "CERN. Why is that name so familiar?"

Ferb tapped his brother on the shoulder, then made a circular movement with his hands.

"Oh, yeah," said Phineas, "the LHC!"

"The LH what?" Candace asked.

"The Large Hadron Collider," Phineas said. "It's designed to collide particle beams into each other so that we can research the very fabric of existence. They even say it could..." then Phineas' eyes widened, his mouth dropped open and he stared at Ferb. Ferb only stared back.

"Phineas," Isabella chimed in looking nervous, "they say it could what?"

Phineas slowly looked to Isabella. "Lead to time travel," he said.

THE FUTURE: YEAR 2015

Phineas and Ferb both rested on their couch, enjoying the warm July day. They both were in high school now but still had summers to enjoy while Candace was in college. Normally the older Candace would still be there, only she was at home during her school's summer break.

No longer did she worry about busting Phineas and Ferb for whatever crazy scheme they may be up to. Candace simply laid on her back on her bed in her room, lazily talking to Stacy on her phone when the signal was abruptly cut off. "Huh?" Candace asked, sounding annoyed.

In the living room, Linda Flynn-Fletcher walked in handing over an envelope to Phineas. "Here you go boys," she said, "looks like you got mail." Just as she finished saying that, the lights went off, as did the television. "Oh dangit," she mumbled, "your dad must be using the power tools again. Probably flipped a breaker." Then she headed to the basement.

Phineas looked at Ferb curiously who only looked back with a blank stare on his face.

Phineas opened the letter. It was hand written in very neat penmanship. Phineas looked to who the letter was from. It made him jump slightly in his chair. "It's from Titor!" he exclaimed. Then he held the piece of paper away from him as if shocked by it, but decided to read it aloud anyway.

"Dear Phineas and Ferb," Phineas read.

Somewhere in the world, alarms started going off. Panicked men started screaming in Russian as missile bay doors opened.

"I'm sorry to say," Phineas continued, "that what I meant to tell you that day when we talked was that you cannot give the computer to CERN, that they will come looking for it. They..." Phineas gulped. "They will only use your programming to solve the problem for themselves, so that the LHC can go on as planned. They do not care about the rest of the world."

Somewhere in the world, a missile stood at the ready to launch. More men screamed at each other in Russian, but none of them could stop what it was about to do.

"I'm sorry to say that CERN has used it to save the LHC but nothing else. The failure of mainframes worldwide will still happen, as will..." Phineas' eyes swelled with tears, "as will the nuclear war that I tried to prevent." Phineas was shaking now and Ferb just gently rested a hand on his shoulder.

Phineas hugged his brother, then went back to reading. "Take comfort in knowing this: The Tri-State area will not be hit and will survive the attack, that the LHC will lead to time travel being developed, and that because of CERN's mainframes being fixed, the rest of the world will be able to get back online, once the nuclear war has completely ended. You will go through hard times, Phineas, but be brave cousin. You will not have to go it alone. You have your family, you have your friends, and you have one other who will make himself known to you soon. By the time you read this, I will be back in my own time, 2036. Some things we cannot change, Phineas. Some things time just will not allow us to change. Even if you have been to the future, it was a future that could never be as it was a future that would happen without my travelling back in time, before I changed your worldline just by being here, before the threat of 2015 was ever accounted for. I either changed your future, or I fixed it, I can't say. Either way I'm sorry. The future is blank, Phineas. We write it, and some things were just not meant to be changed. Good luck, Phineas and Ferb. -John Titor."

Phineas once more fell into his brother's arms, crying, the letter falling to the ground.

Once the piece of paper gently made contact with the floor, the missile, along with hundreds and hundreds of other warheads, suddenly launched from Russia.

Somewhere in a NATO command center, the announcement that Russian nuclear warheads were flying towards various parts of the world came through, and plans for retaliation began.

"You're on your own now, Agent P.," Monogram said to Perry through his wrist communicator after hearing Phineas read the letter. "I suppose we all are now. We will try to continue OWCA, but... it will be a very different world now. Consider the Flynn-Fletcher family your permanent host family now, Agent P. Your mission is to protect them and comfort them, get them through this. I will keep in touch."

Perry smiled weakly, his eyes filling tears as he stood and saluted. Then he put on his hat, and walked forward, both Phineas and Ferb looking down at him curiously.


	7. Afterword

If you're still wondering why the future that Phineas and Ferb went to in the show was so much different than the future they now faced with the nuclear war, it was because Titor traveled back in time and, pretty much, changed the course of their history. This can get a little confusing. As Titor said, going FORWARD in time is easy, as it doesn't change anything in the worldline you're currently in (the future hasn't happened yet). Going back in time, however, is impossible since it already happened, and so quantum physics has to make up a scenario where going back in time is even possible – that is called the string theory, which has an infinite number of worldlines.

Remember the conversation that Titor had with Kevin Flynn – that he had to step into the worldline directly next to his, so that it would be as much like his worldline as possible.

If you didn't like the ending, that's alright. It is only fanfiction after all, and can't change the course of the real show. You can also take into consideration that he show is a different worldline than this story. Either way, I just hope you enjoyed the story.

Special thanks goes to Larry Haber (the attorney for the real John Titor), Oliver Williams (who runs the biggest website dedicated to John Titor), George Noory (host of late night radio show Coast to Coast AM which was the show Phineas stayed up to listen to), Art Bell (former host of Coast to Coast AM), and Anonymous who wrote the excellent book 'Convictions of a Time Traveller', now available from Amazon.

Please take a look at some of my other fanfic, and stay tuned for more. See you in the future.

-H. H.


End file.
